The haemodynamic and metabolic effects of epinephrine in experimental hyperdynamic septic shock

Objective: To study the effect of epinephrine (EPI) infusion on vital organ blood flow and metabolic variables during sepsis. Design and setting: Randomised placebo-controlled animal trial in an animal laboratory. Animals: Seven merino cross-ewes. Interventions: Chronic implantation of flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous injection of E. coli. Random allocation of sheep to EPI (0.4 mug kg(-1) min(-1)) or vehicle for 6 h. Measurements and results: E. coli induced hypotension and hyperlactataemia and increased cardiac output, renal, mesenteric and coronary blood flows. Compared to vehicle, EPI restored mean arterial blood pressure (69 vs. 86 mmHg) and further increased cardiac output (6.4 vs. 7.1 l/min). EPI, however, decreased renal blood flow (330 vs. 247 ml/min) and renal conductance. EPI also reduced mesenteric and coronary conductance without changes in flows. Compared to vehicle, EPI increased urine output (293 vs. 544 ml/6 h) but not creatinine clearance. EPI increased lactate (1.8 vs. 15.7 mmol/l) with accompanying acidosis (serum bicarbonate: 25.2 vs. 15.7 mmol/l), hyperglycaemia ( 2.6 vs. 13.5 mmol/l) and hypokalaemia (4.3 vs. 3.0 mmol/l). Conclusions: Hyperdynamic sepsis increased blood flow to heart, gut and kidney. Although EPI infusion further increased cardiac output, blood pressure and myocardial performance, it was also associated with potent metabolic effects, decreased mesenteric, coronary and renal conductance and a significant reduction in renal blood flow.